ASoC: WM8985: Initial driver

The WM8985 is a low power, high quality, feature-rich stereo
CODEC designed for portable multimedia applications that
require low power consumption and high quality audio.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>